The invention relates to a gear train for a machine for processing flat printing material, in particular a rotary printing machine, having a coupling for separating and closing the gear train, the coupling comprising rotating elements having toothing systems which, in the closed condition of the gear train, are in mutual engagement and, in the separated condition, are out of engagement, and also to a machine for processing flat printing materials, in particular a sheet-processing rotary printing machine, which is equipped with the gear train.
A gear train of the type mentioned at the introduction hereto is disclosed in German Patent DE 44 47 862 C2. The coupling disclosed therein serves for recoupling, with a changed phase angle, a part of the gear train that has been uncoupled by having been separated. Although, when compared with comparable frictional couplings, the formlocking coupling provided for this purpose increases the functional reliability of a rotationally fixed connection between two gears in the coupled condition, it is only possible to adjust to rotational angles corresponding to a multiple of the pitch of the toothing systems at the end faces of the coupling parts, i.e., the rotational angle of one of the two gears with respect to the other is variable only in steps corresponding to the pitch of the toothing systems. For reasons of strength and production, however, the amount of pitch is subject to a lower limit which, assuming a constructionally yet tolerable extent of the diameter of the coupling, cannot be sufficiently small for the positionally-correct adjustment of the aforementioned rotational angle. In the foregoing regard, it is noted that a formlocking coupling is a coupling by which a formlocking connection is made wherein two elements are connected together due to the shape of the elements, as opposed to a forcelocking connection wherein the elements are locked together by force external to the elements.
It is accordingly an object of the invention to provide a gear train for a machine for processing flat printing material so that, with a yet tolerable extent of the diameter of the coupling, a fine angular resolution relative to the mutual rotation of the gears is possible, and so that torque transmissible by the coupling has an adequate magnitude.
With the foregoing and other objects in view, there is provided in accordance with one aspect of the invention, a gear train for a machine for processing flat printing materials, comprising a coupling formed for separating and closing the gear train, the gear train further comprising rotating elements having toothing systems which, in a closed state of the gear train, are in mutual engagement and, in a separated state of the gear train, are out of engagement, a multiplicity of the rotating elements being provided combined into pairs, the toothing systems of one of the pairs of rotating elements having a tooth pitch differing from the toothing systems of a respective other of the pairs of rotating elements.
In accordance with another feature of the invention, the toothing systems of the rotating elements comprise Hirth-type toothing systems.
In accordance with a further feature of the invention, the toothing systems of the rotating elements comprise spur-gear toothing systems.
In accordance with an added feature of the invention, a first and a second of the pairs of rotating elements comprise one of the rotating elements common to both of the pairs.
In accordance with an additional feature of the invention, the toothing systems of the first and of the second pair of rotating elements are constructed as Hirth-type toothing systems.
In accordance with yet another feature of the invention, the rotating element common to the first and the second pair of rotating elements has a Hirth-type toothing system and a spur-gear toothing system, and a correspondingly toothed one of the rotating elements, respectively, is assigned to the common rotating element.
In accordance with yet a further feature of the invention, respectively, an end one of the rotating elements forming the coupling constitutes a gear of the gear train.
In accordance with yet an added feature of the invention, the rotating element common to the first and the second pair of rotating elements has a jacket surface forming a toothing system, the gear train further comprising a setting pinion meshing with the toothing system, the common rotating element being rotatable by the setting pinion when the gear train is separated.
In accordance with another aspect of the invention, there is provided a machine for processing flat printing materials, including a gear train, comprising a coupling formed for separating and closing the gear train, the gear train further comprising rotating elements having toothing systems which, in a closed state of the gear train, are in mutual engagement and, in a separated state of the gear train, are out of engagement, a multiplicity of the rotating elements being provided combined into pairs, the toothing systems of one of the pairs of rotating elements having a tooth pitch differing from the toothing systems of a respective other of the pairs of rotating elements.
In accordance with a concomitant feature of the invention, the machine of the invention is a sheet-processing rotary printing machine.
The object of the invention is achieved by utilizing the features of the multiplicity of rotating elements being provided combined into pairs, and the toothing systems of one of the pairs of rotating elements having a tooth pitch that differs from that of the toothing systems of a respective other of the pairs of rotating elements.
By a realization of the invention, the aforementioned angular resolution can be made many times finer than that of heretofore known couplings, in fact, especially not at the expense of the strength of the toothing systems of the rotating elements forming the coupling. This is because the minimum step width for changing the mutual phase angle of two gear-train sections in the case of a construction of a gear train according to the invention is not limited downwardly by the pitch of the toothing systems of a pair of the rotating elements but, in the case of two pairs of rotating elements, is limited by the pitch difference between the toothing systems thereof, so that heavily loadable toothing systems can be provided. When the toothing systems are constructed in the form of Hirth-type toothing systems, there results, furthermore, the advantages of automatic centering of the rotating elements and freedom from play.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a gear train for a machine for processing flat printing material, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.